The present disclosure relates generally to gas or steam turbines and, more specifically, to an aspirating face seal having improved bearing force and stiffness.
Rotary machines, such as gas turbines, are often used to generate power with electric generators or for aircraft propulsion. Gas turbines, for example, have a gas path that typically includes, in serial-flow relationship, an air intake, a compressor, a combustor, a turbine, and a gas outlet. Compressor and turbine sections include at least one row of circumferentially-spaced rotating buckets or blades coupled within a housing. At least some known turbine engines are used in cogeneration facilities and power plants. Engines used in such applications may have high specific work and power per unit mass flow requirements.
At least some known rotary machines use aspirating face seals to reduce leakage through a gap defined between stationary and rotating components of the gas turbine. Aspirating face seals are non-contacting seals that typically operate with a tight clearance between the stationary and rotating components. In operation, a pressurized fluid is channeled between opposing faces of the stationary and rotating components to facilitate maintaining the clearance therebetween as the components translate relative to each other. More specifically, a biasing face seal of the stationary component and the pressurized fluid facilitate ensuring the clearance is maintained when variations in the axial positioning of the rotating component relative to the stationary component occurs. However, large variations in the axial positioning of the rotating component can briefly overcome the force of the pressurized fluid, thereby resulting in rubbing and wear to the components of the aspirating face seal.